There are links between nations, cordial relations, firm bonds, alliances and strategic partnerships. But what Turkey and Israel had in mind just four years ago was something akin to being joined at the hip. The plan was to snake an extraordinary "infrastructure corridor" from Ceyhan in Turkey's south to Haifa in Israel's north, a thick bundle of pipes carrying crude oil in one, electricity in another, natural gas in yet another and in the fourth, a steady flow of fresh, sweet water, all thrumming along the floor of the Mediterranean Sea. Not only would these pipes serve as ties that bind two nations, but they would also show the world that a Muslim country could tether itself to the Jewish state, to their mutual benefit.

Which makes the events of the past few weeks all the more worrisome for Israel. With dizzying speed, Turkey has gone from offering oil and gas to Israel to threatening to send gunboats to the Gaza Strip to protect activists seeking to break Israel's naval blockade of the Palestinian territory. Enraged by Israel's refusal to apologize for its killing of eight Turks (and one Turkish American) on board a blockade-busting ferry last year, Ankara has ejected Israel's ambassador, downgraded diplomatic relations and imposed military sanctions on its former ally. And that "infrastructure corridor"? It's now a mere pipe dream. (See Israel's thinkers discussing the country's challenges over the next 60 years.)

This conspicuous unfriending could hardly come at a worse time for Israel. As representatives of 193 nations gather in New York City for their annual U.N. conclave, Palestinian leaders are polishing a statehood proposal that would change the fundamental terms of the Middle East's core conflict, possibly putting them on the same legal footing as Israel.

With most of the world sympathetic to the Palestinians, waylaying their application for statehood will require Israel to deploy diplomatic skills of the highest order. But its preparations have not been going well. Prime Minister Benjamin Netanyahu warmed up for the big event by alienating the U.S. President, at once misquoting and lecturing Obama during Netanyahu's visit to Washington in May. Then there's the Arab Spring, which knocked over the Arab neighbor Israel relied on most, Egypt's Hosni Mubarak; last week, the Israeli embassy was attacked by protesters in Cairo while the riot police stood by. The spectacular collapse of the Turkey alliance makes three strikes. (See pictures of Israelis clashing with Palestinians.)

The game's not over. Obama still plans to use the U.S. veto in the Security Council to deny Palestinians full membership. But they could take the matter to the General Assembly, where a vote would likely be lopsided, leaving Israel looking conspicuously isolated. Israelis approach the threats one at a time. The Netanyahu government is avoiding a diplomatic contre temps with Egypt, since the 1979 peace treaty between the two countries is crucial to Israel's defense. The U.N. is easier to criticize, and most Israelis feel it is generally biased toward the Palestinians. "We don't like the U.N.," says Daniel Reisner, a longtime peace negotiator and international-law specialist. "We don't trust it."

And Turkey? In a country where new homes are built with bomb shelters, diplomatic conflict is easily dismissed. "Turkey, Burkey," said Rabbi Ovadia Yosef, spiritual leader of the Shas party, a key member of Netanyahu's ruling coalition. "God Almighty couldn't care less about them. Who are they anyway?" (See TIME's special report "The Middle East in Revolt.")

Although Prime Minister Recep Tayyip Erdogan was once hailed as a vital ally, many Israelis now regard him as a neo-Ottoman, out to revive Turkish leadership of the Muslim world by beating up on the Jewish state. That's certainly how they perceived Erdogan's performance in Cairo, where he said in a Sept. 13 speech to the Arab League that Israel must "pay a price for its aggression and crimes" and that supporting Palestinian statehood was "not a choice but an obligation." Israel, he said, is "the West's spoiled child."

Across town, Palestinian leader Mahmoud Abbas was meeting with the European Union's Foreign Minister, working on a strategy to avoid the U.S. veto in the Security Council. The Europeans were urging Abbas to settle for the status of a "nonmember observer state," akin to that of the Vatican, which he could get from a vote in the General Assembly  thus avoiding the U.S. veto in the Security Council.